The present invention relates to a solution feeding apparatus and a solution feeding method using said apparatus. More particularly, the invention relates to an apparatus and a method which may be used, for example, to replenish a processing solution for processing a silver halide photographic material using an automatic developing apparatus.
Typical examples of methods of processing a silver halide photographic material after exposure of the photographic material to a light image include those which are employed for processing a monochrome photograph and comprised of such processes as developing, fixing, water washing and drying; those employed for processing a color negative film and comprised of such processes as color developing, fixing water washing, stabilizing and drying; and those employed for processing a color paper and comprised of such processes as color developing, bleaching fixing, water washing, stabilizing and drying. These processes are usually conducted with an automatic developing apparatus by using respective processing solutions. As use of an automatic developing apparatus is becoming more commonplace, using a rinse or other substitute solution in lieu of water washing is on the increase. Compositions of these solutions and fixing solutions change as a result of processing a silver halide photographic material. In addition, with the elapse of time, developing solutions and fixing solutions suffer from decrease in their effectiveness due to air oxidation. In order to prevent these problems and maintain the processing solutions sufficiently effective during continuous processing using an automatic developing apparatus, it is common practice to replenish each respective processing solution with a replenishment solution having a composition either the same as or similar to that of the processing solution.
Each solution for processing a silver halide photographic material is usually supplied in the form of a condensed liquid and needed to be diluted with water to a given concentration before actually used. In this case, the dilution has to be done precisely; a silver halide photographic material processed with an inaccurately diluted processing solution may result in a finished photograph having a considerably poor quality.
Some kind of solution, such as a color developing solution or a bleaching fixing solution, is supplied in a plurality of solution parts in order to increase the preservability of the condensed solution by separating ingredients from other ingredients that are not desirable to contact therewith. When actually used, such a solution has to be prepared by mixing the concentrated stock solutions, each of which usually consists of two to four solution parts, while diluting the mixture with water. During this mixing process, various accidents, such as mistaking a solution part for that of another processing solution, often happen. It is not uncommon that such a mistake seriously and irreparably impairs the quality of the finished photograph.
As described above, preparation of processing solutions imposes a heavy burden on the operator, because it is not only complicated but also requires precision. Furthermore, it often happens that a condensed solution or a prepared solution spill or spatter onto nearby objects, such as a human body, clothes or furniture and equipment, sometimes contaminating or otherwise damaging the objects. In order to prevent these problems, it has been practiced to supply each processing solution in the form of a ready-to-use solution, with the conditions of the solution adjusted beforehand. Nevertheless, supplying a solution in the form of a concentrated stock solution still has advantages in that it occupies less space for distribution or storage and that it has superior stability in preservation.
When solutions that have been prepared as above are used as replenishment solutions, the replenishment solutions for respective processing solutions are usually stored in separate replenisher tanks, from which a necessary quantity of each respective replenishment solution for the current stage of processing a silver halide photographic material is fed into a solution tank in the automatic developing apparatus with a pump or by other appropriate means. At that time, as the replenishment solutions in the replenisher tanks are stored in such a state as to be exposed to the air, they present the possibility of becoming concentrated due to evaporation of moisture as well as quality deterioration resulting from air oxidation. Should a processing solution be replenished with a replenishment solution that has thus become deteriorated or changed in quality, effectiveness of the processing solution decreases, resulting in poor image quality of the finished photograph.
Examples of means to prevent such a deterioration include a method that calls for disposing a floating lid or a floating ball in a replenisher tank to cover the surface of replenishment solution and thus reduce the area of the surface of the replenishment solution in contact with the air. However such a method has not yet succeeded in completely isolating a solution from air. In view of preservation of the environment and natural resources, the quantity of replenishment solution used for processing a silver halide photographic material is on the decrease in recent years. Therefore, if a replenishment solution is prepared in the same amount as before, it is stored in a replenisher tank for a longer period of time until it is used up and more prone to change in quality. Further, reduction in the amount replenished presents a problem in that even a minimal change in quality of a replenishment solution would make it difficult to maintain the constant effectiveness of the processing solution in an automatic developing apparatus and influence the quality of the finished photographs.
In order to prevent these problems, it is often practiced in recent years to feed a given quantity of water from a diluent water storage tank into a processing solution tank in an automatic developing apparatus simultaneously with sucking a formulated concentrate of processing solution out of its container and directly feeding it into the processing solution tank. Such a method has a benefit in that it eliminates the necessity of preparation of replenishment solutions. In many cases, the above method calls for a flow sensor installed in a container and acting as a solution depletion sensor to detect the solution in the container has been used up. Accordingly, such a method typically calls for using a stock solution container made of a polyethylene bottle or other hard-type bottle that will be free from the problem of becoming deformed when the content is reduced. When such a bottle is used, the quantity of air inside the container increases with the decrease of the stock solution in the container. Therefore, the method is not capable of solving the problem of the concentrated stock solution deteriorating due to contact with the air. The method presents another problem in that it is difficult to form a structure where the solution depletion sensor is prevented from registering detection by mistake when there still remains the solution in the container. In other words, it is difficult to use up the solution in the container; a certain amount of solution tends to remain in the container and often contaminate a human body, clothes or other objects in the environment at the time of disposal of the used container.
In order to solve the above problems, the applicant of the present invention had previously offered solution feeding methods and apparatuses used for said methods, which are disclosed in Japanese Patent Public Disclosure Nos. 52533-1999 and 102056-1999. The problem of a stock solution deteriorating due to exposure to air can be solved by any one of the above inventions by using a container made of a deformable material as a container to be filled with a concentrated stock solution and inserting a tube or other appropriate member into the stock solution container so as to suck the solution out of the container while maintaining the container airtight. Although the container is flexible, each one of the above inventions is capable of precisely detecting that the solution in the container has been used up.
However, each one of the above inventions has a drawback such that, for various reasons, the solution in a container sometimes fails to be fed accurately to the end, i.e., until the container is completely empty. Said various reasons typically include erroneous detection by a gas detection sensor and the air inadvertently entering the pump.
To be more specific:
(1) insufficient separation of gas from a solution in a gas-liquid separation tank or failure in directing the separated gas quickly into a gas trap section sometimes allows the gas mixed in the solution to escape from the gas-liquid separation tank into the pump, resulting in poor accuracy in the solution feeding rate;
(2) in cases where a tube or the like is not inserted deep enough into the container to reach the bottom of the container, the tube tends to suck in air from the container and activates a gas detection sensor prematurely, causing the solution to remain in the container;
(3) in cases where the output rate of the pump is insufficient, even after the solution in the container is completely suctioned out, the gas in the gas trap section fails to expand properly and prevents the sensor from detecting that the container is empty, consequently making it impossible for the operator to know precisely when to replace the container with a new one so that the operator may delay in replacing the container and suspend the supply of the solution;
(4) should the end of the tube or the suction inlet of a needle attached to the tube inserted in the container come into close contact with the inner wall of the container and prevent the tube from sucking in the solution, negative pressure may be generated in the solution conduit and cause erroneous actuation of the gas detection sensor, even when there is some solution remaining in the container; and
(5) when the gas that has inadvertently entered the solution conduit is pushed back into the container, it sometimes happens that a part of the gas enters the pump without going back into the container.
In cases where any one of the aforementioned inventions is applied as a replenishing device incorporated with an automatic developing apparatus for processing silver halide photographic materials, the drawbacks described above may cause changes in compositions of processing solutions in the processing solution tank in the automatic developing apparatus or a processing solution to contaminate the body or clothes of a human when its container is replaced. For this reason, there has been a demand for improvement which prevents these problems from occurring in any circumstances.
Furthermore, each one of the above inventions has a structure such that the sensor or the equivalent means detecting complete consumption of the solution in the container automatically stops feeding of the solution or actuates an alarm to prevent the air from inadvertently entering the pump. This procedure is followed even when the solution is consumed in normal circumstances, requiring the operator to quickly replace the container each time. Delay in replacement is not desirable, because it prolongs the state where supply of the solution is halted. However, as it is not easy to have an operator constantly attend to the apparatus and replace the container immediately each time it is necessary, it often happens that feeding of the solution is halted for a long period of time.
A maintenance method employed at an unmanned processing laboratory often calls for an operator to patrol so as to visit each laboratory once every several days and prepare and add a replenishment solution only to each replenishment solution that has run low. Compared with such a method, each one of the aforementioned inventions is advantageous in that it eliminates the necessity of preparation of each solution and prevents deterioration of the solution for a long period of time by preventing the solution from being exposed to the air. On the other hand, the aforementioned inventions have such a drawback in that it is not possible to refill a container with a solution; unless a container happens to be empty when the operator comes to check, he has to either wait for the next visit to replace the container or proceed with replacing the container and disposing of the solution remaining in the replaced container. Therefore, the arts offered by the applicant are difficult to be applied to a case where such a maintenance method is employed.
In order to solve the above problems, an object of the present invention is primarily to provide a solution feeding apparatus and a solution feeding method which are capable of feeding solution from its container while maintaining precise feeding accuracy to the end of the feeding process. Another object of the invention is to ensure the solution remaining in the container to be completely consumed regardless of the distance by which a tube or the like is inserted into the container. Another object of the invention is to provide a reliable way to detect depletion of the solution and control the pump regardless of whether the pump has a low output rate, wherein detection is registered only when the solution in the container has completely been consumed. Yet another object of the invention is to reliably separate however tiny bubbles from the solution and thereby prevent them from entering the pump. Yet another object of the invention is to prevent the container from being torn even in cases where the container is of a type suitable to be used by being pierced with a tube. Yet another object of the invention is to enable the automatic solution feeding which can container for a long period of time, thereby reducing the task of replacing containers and facilitating the maintenance and management of solution feeding.
In order to attain the above objects, a feature of the invention lies in that a container hermetically containing a solution is made of a high polymer that permits the container to change its shape in accordance with the amount of its content; the container is removably connected to a tube for forming an isolated conduit extending from the container via a pump to the destination to which the solution is fed; said isolated conduit is provided with a gas-liquid separation tank for separating gas from the solution and a gas trap section communicating with the gas-liquid separation tank, the gas-liquid separation tank and the gas trap section located between the container and the pump; and that said gas trap section has a variable volume. The second feature lies in that a desired number of isolated conduits extending via respective pumps to the destination to which the solution is fed are formed by connecting a tube to each container hermetically containing a solution and made of a high polymer that permits the container to change its shape in accordance with the amount of its content; each isolated conduit is provided, at a location between the associated container and the pump, with a gas-liquid separation tank for separating gas from the solution and a gas trap section communicating with the gas-liquid separation tank; and that any one of the isolated conduits may selectively be operated by means of each respective gas detection sensor installed in the corresponding gas trap section. The third feature of the invention lies in that a solution is sealed in container which is made of a high polymer and capable of changing its shape in accordance with the amount of its content; a tube for forming an isolated conduit extending via a pump to the destination to which the solution is fed is connected to said container; said isolated conduit is provided, at a location between the container and the pump, with a gas-liquid separation tank and a gas trap section communicating with the gas-liquid separation tank, said gas liquid separation tank adapted to separate the gas that has entered the conduit from the solution, and the gas trap section adapted to confine therein the gas separated in the gas-liquid separation tank; and that said gas trap section has a variable volume, although the gas-liquid separation tank is ensured to maintain a constant volume until all the solution in the container is consumed.